1. Field of the Invention
The present invention relates to a conical twin-screw extruder and a dehydrator for use in dehydration of water-containing raw materials such as thermoplastic elastomers, rubbers, resins, and the like which contain water, respectively.
2. Description of the Related Art
There is known a dehydrator described in Japanese Unexamined patent application publication No. 2001-353719 as a dehydrator useful for water-containing raw materials. In FIG. 2 of this Patent Document, a technique is disclosed by which a conical single-screw extruder is used as a dehydrator, and a parallel twin-screw extruder is arranged in tandem to be used as a dehydrator.
Referring to the above-described known dehydrator, a water-containing raw material to be supplied should have specifications corresponding to a machine. Thus, there has been a problem in that the dehydrator can not be applied to various types of raw materials.
In particular, in some cases, the hydrator can not constantly nip all of the materials ranging from a powdery raw material to a raw material in a large block shape having a diameter of more than 200 mm. Therefore, problems occur in that variations in processing amount are caused when the dehydrator is used. Moreover, there are some cases in which no production can be performed with raw materials supplied, depending on the shapes and sizes thereof.
Moreover, dehydrators of known types can be applied to raw materials having a water content of about 10% to 40%. Problematically, the dehydrators can not process raw materials having a water content of about 80%, raw materials containing a large amount of water, e.g., those which are conveyed together with water, and so forth.